|
|
| Proper name |
Zinc
|
| Category |
Mineral
|
| Functions |
Zinc
plays a role in over 300 enzymes, including alcohol dehydrogenase (the enzyme
that breaks down and detoxifies alcohol), cytochrome C (necessary for cellular
energy production and transportation), carboxipedidase (needed to digest
dietary protein), superoxide dismutase (a potent free radical scavenger),
alkaline phosphatase (bone metabolism), carbonic anhydrase (which helps
excrete carbon dioxide), etc. Facilitates wound healing, especially wounds
of the skin, such as burns and lacerations. Is useful in the treatment of
acne and excema. Necessary for proper functioning of the immune system,
including T lymphocytes, natural killer cells, interleukin 2, CD 4 and superoxide
dismutase. Zinc lozenges have been shown to reduce the length and severity
of colds. Zinc has been used to support immune function in patients with
HIV. Necessary for the synthesis of DNA and RNA, protein synthesis, cellular
division and gene expression. Zinc is also necessary for ovulation, fertilization
and the maturation of sperm. Zinc is used to treat male infertility and
benign prostatic hypertrophy. Helps regulate the release of Vitamin A from
the liver and is needed to support dark adaptation in night vision. Involved
in endocrine function. Helps convert thyroxine to triiodothyronine. Is a
component of insulin. Important in the sense of taste and smell, especially
salty taste. Persons deficient in zinc have a diminished sense of taste
and often a diminished appetite. Useful in the treatment of anorexia. Anti-inflammatory
effects reportedly useful in arthritis. |
| RDA |
15
mg/day |
| Therapeutic
dose |
30
to 120 mg/day, divided dose. |
| Deficiency symptoms |
White
spots on fingernails, frequent infections, acne, excema and other skin rashes,
indigestion, malodorus intestinal gas, decreased interest in sex, male infertility,
patchy hair loss, poor wound healing, delayed onset of puberty, dwarfism,
night blindness, photophobia, loss of sense of taste, anorexia. A number
of disease conditions are also associated with zinc deficiency including:
diabetes, alcoholism, macular degeneration, melanoma, liver and kidney disease
and malabsorption disorders such as Crohn's disease. In pregnancy, deficiency
can cause birth defects, low birth weights and impaired fetal development.
In conjunction with vitamin A deficiency, low zinc also contributes to stretch
marks. |
| Toxicity |
150
mg/day or greater for prolonged periods can be toxic. Sources of exposure
to high doses of zinc include: cooking acidic foods in galvanized cookware,
welding fumes and galvanized plumbing. Symptoms of toxicity include vomiting,
diarrhea, dizziness, drowsiness, muscle incoordination and lethargy. High
levels of zinc depress serum copper levels. |
| Best
forms
|
Zinc
gluconate or Zinc picolinate ( especially in cases of pancreatic insufficiency).
|
| Food
sources |
Lean meats, liver, oysters and other seafood, eggs and whole grains. |
| Lab
tests |
Serum and urinary zinc Leukocyte (white cell) zinc |
| Drug
interactions |
The
following drugs deplete zinc: Ethambutol, corticosteroids, reverse transcriptase
inhibitors, diuretics, ACE inhibitors, chlorthalidone, oral contraceptives
and estrogen replacement therapy, H2 receptor antagonists and penicillamine. |
| Nutrient interactions |
Iron
inhibits zinc absorption when consumed in a 3 to 1 iron to zinc ratio. Zinc
intake lowers copper levels. Dietary fiber can inhibit zinc absorption.
Extensive use of alcohol can depress zinc status |
| Metabolism |
Requires zinc binding
ligand (produced in pancreas) to be absorbed. Transported in blood by
albumen. Excreted primarily through the intestines.
|
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